Recently, a dispute has erupted over computer viruses or SPAM mail, spyware, phishing fraud, or one-click (or two-click) fraud in Internet communication. In Internet communication, a DoS (Denial of Service) or attack (unauthorized access) from an unspecified counterpart becomes a threat to a server that transmits information such as contents or the like. Also in public telephone networks or IP (Internet Protocol) telephone networks, phone calls for money transfer fraud, SPAM, or phishing fraud or the like occur in addition to conventional malicious phone calls or silent phone calls.
For this reason, as a function required for a phone or a phone book, there is needed a function of denying a response to others except a reliable counterpart, that is, a function of denying the reception of a malicious call or money transfer fraud call in the case of call reception. To avoid the above-described problem, a caller number display function is reliable identity verification for a caller as a function in the case of call reception/transmission. In the case of call reception, there is a method by which an intermediary contact person is allowed to make contact after first receiving a phone call from an unknown counterpart. In the case of call reception/transmission, there is a method of notifying only reliable partners of a telephone number without loading the telephone number into a public telephone book.
In the designation of the communication destination of transmission, the designation is made using information from a local telephone book or a reliable telephone book service. There may be considered a method in which the guidance of an invalid number is provided in the case of call transmission, or conversation with the other party is made after connecting a phone call to a secretary instead of oneself upon call transmission. In this regard, the caller identity becomes clear in the case of call transmission, but there is a problem in that a desired state (location privacy) for preventing others from learning a calling location is not achieved.
On the other hand, as a coping strategy to protect the security of a site even on the Internet, there is a strategy using NAT (Network Address Translation) or a coping strategy at a site border such as DMZ (DeMilitarized Zone), Firewall or the like. For example, this type of coping strategy is disclosed in Patent Document 1 (JP-A-2004-248185), Patent Document 2 (JP-A-2004-248198), and Patent Document 3 (JP-A-2006-050081).
In this case, when an attack has occurred, there will be a reaction such as the case where a common user may not be able to access a site. In terms of recovery/measure when the attack has occurred, recovery is not possible as long as a fundamental measure against the attack is not provided. In terms of access to a site server and a waiting method, there is a weakness in that the possibility of undergoing an attack is high since always wait for all counterparts using the same single fixed address.    [Patent Document 1] JP-A-2004-248185    [Patent Document 2] JP-A-2004-248198    [Patent Document 3] JP-A-2006-050081